Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover read-only/idempotent/non-destructive, and the description adds substantive traits beyond them: cusp handling with ingress plus uncertainty, a no-guessing guarantee, the fallback of considering all local-day conversions when no timezone is given, and an explicit privacy statement that no birth data is stored or logged.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with purpose, then edge-case and privacy notes in tight clauses with no filler. The quoted multilingual trigger phrases add length but earn their place for matching user utterances.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists so return values need no explanation, and the description covers the domain-specific risks (cusp ambiguity, timezone absence, privacy) that an agent would otherwise have to guess at.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With only 25% schema description coverage the description must carry weight, and it does explain the trickiest parameter (timezone optionality and its all-local-day fallback) and how birth_time changes behavior. It says nothing about the lang fallback parameter, leaving one gap.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (find) and resource (Sun zodiac sign) plus the exact input that drives it (birth date), and lists natural-language triggers in EN/IT. An agent can distinguish this single-sign lookup from siblings like get_big_three or calculate_birth_chart.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives clear usage conditions: use for 'what is my zodiac sign' style queries, cusp dates are resolved with ingress/uncertainty rather than guessed, and when a time is supplied the caller should ask for a timezone. It does not explicitly name a competing sibling to route away from, so it stops short of a 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.